class Animal
    constructor: (options) ->
        {@name, @age, @height = 'average'} = options
    move: (meters) ->
        console.log @name + " moved #{meters}m."
class Snake extends Animal
    move: ->
        console.log "Slithering..."
        super 5
class Horse extends Animal
    move: ->
        console.log "Galloping..."
        super 45
sam = new Snake name: 'jrp', age: 4  # 会被 coffee 惯坏的...
tom = new Horse name: 'dr', age: 4
sam.move()
tom.move()
